Fuel feeding system



F 1936. E. A. ROCKWELL FUEL FEEDING SYSTEM 3 Sheets-Sheet 1 OriginalFiled March 5, 1930 Feb. 18, 1936. E. A. ROCKWELL FUEL FEEDING SYSTEMOriginal Filed March 3, 193C 3 Sheets-Sheet 2 fizz/62W fiziuard[Zfiockwedi Feb. -18, 1936.

E. A. ROCKWELL FUEL FEEDING SYSTEM Original Filed March 3, 1930 3Sheets-Sheet 3 frzaerZZ'r Edward @BOQ/ZZZ/l My i I I i Patented Feb.18,- 1936 PATENT, OFFICE FUEL FEEDING SYSTEM Edward A. Rockwell,Chicago, 1]].

Application March 3, 1930, Serial No. 432,743

. Renewed June 2, 1933 5 Claims. (Cl. 123179) This invention relates toimprovements in fuel feeding system for internal combustion engines andmore particularly to systems in which troubles due to accumulation of.liquid fuel in the intake manifold are avoided and the fuel economy ismaintained by preventing wastage of the excess liquid fuel which isdelivered by the carbureter to the intake manifold.

It is well recognized that in general more power may be secured withdown-drag! carburetion than with up-draft carburetion ut the use ofdown-draft carbureters in connection with internal combustion engineshas disclosed certain difliculties in operation. If the venturi or ofthe down-draft carbureter is proportioned for maximum power at highspeeds, there is so little vacuum in the venturi at low speeds when theengine is started with wide open throttle that a greater quantity offuel must be fed than is actually utilized to give the desired mixtureand, therefore, the excess liquid fuel accumulates in the lower part ofthe intake manifold and it has been customary to utilize a drip tube tospill out such excess liquid fuel. It is sometimes impossible to startthe engine with a partially closed throttle since suflicient air is nottaken in to form the fuel mixture to start the engine and flooding ofthe manifold takes place, as the high vacuum prevents draining throughthe drip tube. Furthermore, flooding of the intake manifold may occur ifthe vehicle with a heavy load. It is highly desirable that some means beemployed for preventing the wastage of. the excess fuel whichaccumulates in the intake manifold, Because of the fuel wasted it hasnot been possible to use down-draft carbureters proportioned to givemaximum power since, as the area at the throat of the carbureter isincreased, more fuel isswasted on while the engine is under load.

According to my previous application, Serial No. 409,538, filed November25, 1929, I have disclosed a system for feeding fuel from the supplytank directly to the mixture chamber of. a downdraft carbureter by meansof a pump mechanically driven from the engine, which pump has a flexiblediaphragm resiliently limited in its discharge stroke. In this previousapplication the fuel delivered by the'pump has been further controlledby means of a pressure tube which leads from the intake manifold beyondthe carbureter throttle to the backside of the flexible pumping memberwhereby a high vacuum in the intake manifold assists in cutting downthe. delivery of fuel by the pump and an opening of the throttle throatis traveling at open throttle starting and resulting in substantiallyatmospheric pressure in the intake manifold causes an atmosphericpressure to be applied to the back side of the pump diaphragm and allowsthe full force of the resilient discharge means to be employed forproducing a. high delivery of. fuel for purposes of acceleration. It isnecessary in such construction to provide some means for bleeding airinto the pressure tube in order to obtain the correct regulation ofpressure applied to the back side of the pump diaphragm.

It is a purpose of the present invention to provide a system in whichthe excess liquid fuel accumulated in the intake manifold is not wastedbut is returned to the carbureter and preferably the return isaccomplished by sucking the excess liquidfuel into the intake side ofthe pump which serves to deliver fuel from the supply tank to thecarbureter.

It is further an object of the present invention to trap the excessliquid fuel into a float-controlled atmospheric chamber in which a floatoperates upon a rise of. the liquid level to open an outlet valve and asecond suction-operated valve is provided which normally prevents theflow of fuel from the supply tank into the float trap chamber should thevehicle be in such position that the supply tank produces a head of fuelon the outlet from the trap chamber. The suction valve is operated bythe suction of the pump to permit the fuel to be drawn out of the trapchamber and delivered to the intake side of the pump.

It is further a purpose of the present invention to combine a system forpreventing wastage of the excess liquid fuel with a system such asdisclosed in my previous application whereby the opening through whichthe excess liquid fuel is passed from the intake manifold into the trapchamber also serves as the restricted vent for bleeding air into thepressure tube which connects the intake manifold to the back side of thepump diaphragm. Another important object of the present inventionconsists in improving'the quick starting of the earbureter throat maythen flow out of the manifold or'into the trap chamber since thepressure in the; manifold will be substantially atmospheric. Otherwiseit is apparent that the excess "fuel would not flow out and the manifoldwould be flooded. By the use. of such a system the fuel may be drainedand returned to. the supply line and the highest efliciency obtained.

engines having down-draft carbureters by requir- 45 fdelivered byth'ep ppreferred cginstru tion pumping di pin .75

Further and additional objects will be more readily apparent from thefull description given in connection with the attached drawings in whicha preferred embodiment of the invention is illustrated.

In the drawings:

Figure 1 is a substantially diagrammatic illustration of an internalcombustion engine having the present improvements applied thereto.

Figure 2 is a vertical section taken through the pump which serves todeliver fuel from the supply tank to the carbureter.

Figure 3 is a vertical section taken through the float-controlled trapchamber and illustrating the manner in which the excess liquid fuel isdelivered from the intake manifold to the trap chamber and from the trapchamber into the pipe line which leads to the intake of the pump.

Figure 4 is a vertical section taken through the Venturi throat of thedown-draft carbureter and illustrating the arrangement of the choke andthrottle valves.

Figure 5 is a partial diagram of linkage, and

Figure 6 is a partial vertical section illustrating a construction foroperating the throttle linkage at the same time as the engine starter isactuated.

In the drawings an internal combustion engine is diagrammaticallyillustrated at II, in Figure 1, and has associated therewith an intakemanifold l2 for delivery of the fuel mixture into the engine cylinders.According to the preferred construction, a down-draft carbureter I4 isutilized for feeding the fuel mixture downwardly into the intakemanifold but it will be apparent that certain features of the inventionmay be applicable to systems in whichan up-draft is utilized. A fuelpump 16 is mounted on the engine casing and is mechanically driven froman engine cam shaft in a. well-known manner. The fuel pump serves tosuck fuel through a line i! from a supply tank 20 and deliver the fuelthrough a pipe line 22 which leads to the carbureter M. The details ofthe oarbureter are more fully described in my copending application,Serial No. 409,538, filed November 25, 1929, but, by referring to Figure4, it will be understood that a vertical tube 24 is provided having atits upper end a choke valve 26 and at its lower end a throttle valve 28.A venturi 30 is provided at the mid-portion into which the fuel isdirectly delivered from the pipe line 22 through the central deliveryorifice 32. A valve the throttle 34 closes the fuel conduit when thecarbureter is inactive. Suction produced in the intake manifold duringthe starting of the engine will be communicated to a diaphragm 36 whichwill effectuate an opening of the valve 34 against the resistance of aspring 38. The valve 34 is further intended to be controlled by a lever40 actuated by movement of the throttle 28 whereby the valve 34 isclosed when the throttle is in idle position and the fuel is thensupplied through an auxiliary inlet, which is not shown in the presentdisclosure, and when the throttle is open wide for starting purposes,the valve 34 is opened by movement of the lever 40 in order to permitdelivery of the fuel into the mixture chamber of;

the

ca rbureter. ,7 -i i i The construction of the-fuel Dl H R anydesirableform in whichi a, I stant resilient ressure maint l ili h li iis; pdsltivly movedjinfa 4 l e .4. tu-

e in new? 1 F19 suction direct ated from the engine cam shaft and isresiliently urged in a discharge direction to take a variable stroke bythe action of the spring 46, enclosed in a chamber 48 on the back sideof the pump diaphragm. The pumping chamber 50 is in communication with afuel-receiving and trapping chamber 52 through a spring-pressed inletvalve 54. The supply line i8 from the supply tank leads into thefuel-receiving chamber 52 through a centrally disposed intake 55. Thedelivery from the variable capacity pumping chamber 50 is through aspring-pressed discharge valve 58 into a chamber 50 from which the fuelis delivered through the pipe line 22. An air dome and vapor trap 62 isprovided to maintain a uniform delivery from the pump. A pressure tube64 communicates with the intake manifold and the chamber 48, on the backside of the pump diaphragm, as shown in Figure 2, and serves to producepressure variations in the chamber 48 corresponding to the changes inpressure in the intake manifold. A plug Iii is threaded into the pumpcasing and has a restricted orifice 68 for bleeding air into the chamber48 and the tube 84 is generally provided with an additional air bleedadjacent to its connection to the intake manifold.

The apparatus for draining the fuel from the intake manifold is shown indetail in Figure 3 in which the intake manifold is formed with adepressed trap chamber 18 which serves to collect the excess liquid fueland a threaded plug 12 is secured to the intake manifold to form thebottom of the trap chamber. A secondary trap chamber 14 is provided forreceiving the fuel from the manifold trap chamber 10 and, in thedisclosed construction, is attached to a T-shaped head 16 inserted inthe pipe line It which leads to the intake for the pump. A valve seatmember 80 is pressed into the upward extension of the T- shapedconnection 18 and cooperates with a valve 82 controlled by movement of afloat 84 having a stem 88. The valve seat member 80 further serves as aseat for an upwardly pressed check valve 88 maintained normally inclosed position by a spring 30 which is positioned by a stem 92 carriedby a removable threaded head 94. The top of the chamber 14 is flanged,as at 86, and has seated thereon a perforated strainer plate 88 and anadditional cover I00 having a flange I112. The perforated strainer 98serves to filter the air which is drawn into the intake manifoldcounter-current to fuel delivered into the fuelcollecting chamber 14 andtends to keep dirt out of the liquid fuel which collects in the chamber14. The outside cover Hi0 and the strainer plate 88 are secured to thechamber 14 by means of the bolt and nut connections I04. The cover I00has openings I06 which permit atmospheric pressure to continuously actupon the fuel in'the chamber I4 and permit air to be drawn into themanifold counter-current to the fuel delivered into the chamber 74. AT-shaped union 108 is threaded at its upper end into the plug 12 andextends downward into the trap chamber 14 .through a flanged opening H0of the outer cover "gland an opening in the strainer plate 38. The

...; l9werend of the connection N18 has a perforated ,c ap H2 securedthereto which forms a guide for the upper .end of the float stem 86. v

the fuel from the manifold trap chamber el ,19 is delivered throughopenings I I4 into the vertilcalpassage H6 formed in the union )8 andthen 1 jp asses through a restricted opening H8 therein viifrom wl ichthe fuel is delivered through the openings I20 formed in the cap H2 intothe chamber I22 within the trap I4. As the level of the fuel collectedin the chamber I22 rises, the float valve 82 will be lifted from itsseat and permit the fuel to pass in communication with the check valve88 whereupon the suction produced in the pipe line I8 will serve to openthe check valve 88 to cause the fuel collected in the chamber I22 topass to the intake side of the pump together with the fuel from thesupply tank. The

fuel will be sucked out from the trap chamber until the float valveagain closes, and, it will be apparent that the provision of the floatvalve prevents air from being drawn into the pipe line I8 which wouldprevent priming of the pump. Further the provision of the check valve 88prevents fuel from being delivered into the trap chamber from the supplyline I8 should the vehicle be in such position that the supply tankproduces a head of fuel on the passage which leads into the trap chamberfrom the pipe line I8.

The restricted opening H8 formed in the duct which delivers fuel fromthe manifold trap to the chamber I22 prevents excessive air from beingdrawn into the intake manifold under vacuum conditions which mightdisturb the mixture of fuel and air pr (1 by the carbureter. Anotherfunction of the restricted opening II8 con sists in the fact that theopening I I8 serves as an air bleed for the pressure tube which is alsoconnected to the Tshaped union I88 by a threaded connection I24. 7

In starting engines provided with down-draft carbureters, it is highlydesirable, in fact, almost necessary, that the throttle be moved to wideopen position in order to admit suflicient air for starting purposes andto allow draining of the excess fuel. According to the presentimprovements, I have provided a form of linkage in which operation ofthe starter button causes the throttle to be immediately moved to wideopen position and upon release of the starter button, the throttle isreturned to the position determined by the hand throttle or footaccelerator.

In Figures and 6 somewhat diagrammatic representations'of the linkageare shown. I38 is a lever connected to the throttle rod I32. A bellcrank lever I34 is mounted on a pivot I36 and. has one arm connected bythe rod I38 to the lever arm I38. The other arm of the bell crank leveris connected by a rod I48 to a bell crank lever I42 having one arm I44connected to the rod I48 and the other arm I46 connected toa rod I48which extends to the accelerator and has a lost motion connection I58extending to the manual throttle control. The bell crank lever I42 ispivotally mounted on a shaft I52 adjacent a pivoted lever I54 which hasan extension I56 extending to come intocontact with and pick up anextension I58 of the lever arm I44. The lever I54 is suitably connectedby a rod I68 to be operated by movement of the starter button.

It will be apparent that any desirable connections may be employed forinsuring movement 'of the rod I68 to effectuate an opening movement ofthe throttle prior to or simultaneously with the operation of thestarter of the engine. In general, it will probably be desirable incases where the starter button merely serves to close electricalcontacts to have a separate lever which is given a movement prior to theoperation of the starter button in order to have suflicient movementimparted to the rod I68 to move the throttle to wide open position. Oneform of arrangement is substantially diagrammatically illustrated inFigure 6 in which I62 is the floor board of a vehicle having mountedthereon a switch member I 84 operated by movement of the button I66 inorder to close the electrical circuit indicated at I68. A bell crankpedal lever H8 is carried by a pivot I12 beneath the'floor board beactuated by the operator. The lever arm "6' includes a dependingprojection I82 which, upon pivotal movement of the lever I18, comes intocontact with" and operates the starter button I66. In order to hold thelever I18, the rod I 68, and the lever arm I54 in normally inoperativeposition, a spring return I84 is provided connected from a fixed point'I86 to:the lever arm I54. The linkage by which the foot acceleratoractuates the throttle may be held in released position by a springreturn such as indicated at I88 connected from a fixed point I98 to thelever arm I38.

The operation of the linkage will be as follows: The operator, to startthe engine, steps upon the lever I18 and during the first part of themovement the throttle of the carbureter is moved to wide open positionsince the movement of lever arm I54 will cause the bell crank lever I42to be picked up and moved. During this movement the connection I58 willremain stationary together with the hand throttle usually associatedwith the steering wheel. As soon as the engine is started the operatorreleases the pressure upon the lever 118 which is thereby immediatelyreturned by the force of the spring I84. The throttle linkage will,therefore, be returned by the spring I88 and the normal operation by themovement of the accelerator or hand throttle may take place. Theadvantage of such arrangement will be readily apparent since theconstruction absolutely insures that the throttle will be wide open-when the engine is started and thereby insures atmospheric pressure inthe intake manifold and therefore any excess liquid fuel which mayaccumulate in the intake manifold will immediately drain out into thetrap chamber.

Various modifications and changes may be resorted to in the particulararrangement of the connections and parts without departing from thespirit of the invention as expressed in the appended claims.

I claim:

1. In combination with an internal combustion engine having an intakemanifold, a down-draft carbureter for, delivering fuel downwardly intosaid intake manifold, a throttle valve for controlling the mixture flow,means for draining excess liquid fuel from the intake manifold from apoint on the engine side of the throttle and means for insuring theopening of the throttle valve as the engine is started to obtainsubstantially atmospheric pressure in the intake manifold in order topermit draining of the excess liquid fuel therefrom.

point on the engine side of the throttle through a restricted passageinto said atmospheric chamber and means for positively insuringsubstantially atmospheric pressure in the intake manifold as the engineis started .in order. toalloy flow of the excess liquid fuel from theintake manifold into said collecting chamber.-

3. In combination with an internal combustion engine having an intakemanifold, a down-draft carbureter for delivering the fuel mixturedownwardly into the intake manifold, a throttle" valve forcontrollingthe mixture flow into said manifold, means for drainingexcess liquid fuel from the intake manifold from a point on the engineside of the throttle valve, means, for returning the fuel drained fromthe intake manifold to the carbureter and means for insuring that thethrottle valve is in openpositionas' the engine is started to producesubstantiallyatmospheriopressure in the intake manifold and permitdraining of excess liquid fuel therefrom.

4. In combination with an internal combustion engine having an intakemanifold, a carbureter for supplying the fuel mixture to the intakemanifold, a throttle valve for controlling the nowof the, fuel mixture,means for draining excess fue I from, the intake manifold from a pointon the engine side of the throttle valve, starting means for the engineand means for insuring the opening of the throttle as the starting meansis actuated to produce substantially atmospheric pressure-in the intakemanifold to permit draining of the excess liquid fuel from the intakemanifold.

5. In combination with an internal combustion engine, having an intakemanifold, a down-draft carburetor for delivering the fuel mixturedownwardlylnto said intake manifold, a throttle valve for compelling themixture flow, means for drainingtemesslliquid fuel from the intakemanifold from a point on the engine side of the throttle,

starting means for the engine and means for pressure in the intakemanifold and permit drainpi the excess liquid fuel therefrom.

EDWARD A. ROCKWELL.

